The subject matter of this invention relates to improvements for receivers of the type used to receive transmitted broadcast video signals and particularly, although not necessarily exclusively, the digital signal receiver. A digital receiver allows the transmitted data which is in an encoded format to improve efficiency and reduce code length, to be received, decoded and displayed on screen for viewing.
A known problem with digital data receivers is that while they decode and display broadcast information efficiently they are at present only capable of acting as xe2x80x9creal timexe2x80x9d processing devices and do not hold any significant historical information. This means that the viewer of the television or other means connected to the receiver is denied the opportunity to repeat the last quantity of video data to be displayed in normal replay or slow motion mode. This is however a feature which has been found to be desirable as the viewer may wish to review some material which has previously been displayed and can be used in many different functions such as, for example, when viewing sports events to look at a goal or particularly skillful piece of play.
The aim of the present invention is to allow the ability for a receiver to be provided with replay and/or slow motion functions for video content which is received and displayed on a television set or other display medium.
In a first aspect of the invention there is provided a receiver for the reception of transmitted data and generation of a display of the video data on a display screen connected therewith, said receiver including a physical memory in which video data is stored and from which, for a time period following display, said video data can be selectively retrieved to create a video display on the display screen and characterised in that said memory includes a first portion of memory which receives the most recently transmitted data received by the receiver at each instant, and a remainder portion in which is stored, in sequence, packets of data which have previously been received and displayed and have been transferred from said first portion over time.
In a preferred embodiment of the apparatus there is provided a transmitted data receiver for the reception of data and generation of a display of the video data on a display screen and wherein said receiver includes a physical memory, in which video data is stored, which video data can be selectively used to create a video display on the display screen and the memory includes a first portion which acts as a moving buffer memory portion which moves and is updated with the passage of time and into which the most recently displayed data packets are stored. Over time the first portion is updated with more recent data packets and the data packets previously held in the first portion move into the second portion of the memory which stores the data packets in time order for a period of time, the length of which can be determined at least partially by the size of the memory. Typically a circular memory construction is used and, as the first portion xe2x80x9cmovesxe2x80x9d around the memory, and is updated and receives the most recently displayed data, so the oldest data held in the second portion is overwritten and this process continues as data continues to be processed and displayed by the receiver. Thus in a preferred embodiment, at any one time, the memory, in accordance with the invention, holds data which has most recently been processed and displayed and further data in time order therefrom up to a certain historical time limit and the data held in that memory can be retrieved for display upon command by the user of the apparatus and in one of plurality of user selectable formats.
In one embodiment the video data stored in the memory has been used to generate a video display.
Thus the memory receives data from the data transport stream from the broadcaster and the same is used to generate the video display and at the same time is stored in the physical memory so that at any instance a predesignated quantity of the most recently received data is readily available in the memory.
Preferably the memory is a circular buffer memory in operation which means that the content of the memory at any one time is successively overwritten as new packets of video data are routed to and through the memory to replace the oldest data in the memory and so on.
Preferably the capacity of the memory is set so as to be sufficient to allow the storage of meaningful quantities of data so as to facilitate the storage of a displayed video content or a series of packets of data so that the video packets are accessible for a predetermined period of time following display to allow the same to be replayed or for the same to be used in slow motion . Typically the length of the video packets which can be viewed after initial display is directly proportional to the size of the buffer memory provided and the capacity is such as to allow a video display of a meaningful length to be displayed in slow motion or replay mode.
In a further feature of the invention, the display interrupt at the video driver layer can be manipulated in respect of the contents of the buffer memory so that the same can be displayed at variable speeds to achieve the effect of variable slow motion.
In a further aspect of the invention there is provided a method of receiving and displaying transmitted data, said method comprising the steps of:
encoding a stream of data into digital encoded data;
transmitting the encoded data for reception by at least one data receiver;
decoding the received data into a form for the generation of a video display on a display screen connected to the data receiver and characterised in that the data receiver includes or is connected to a memory in which the received data can be stored for selected retrieval within a time period after the initial display to create a video display, and wherein said memory includes a first portion into which the most recently received data is placed, and a remainder portion into which data from the first portion passes.
In one embodiment the received data is simultaneously decoded to create the video display and saved in the memory for selective use in generating a display.
In one embodiment the memory contains packets of received data with the oldest packets of data overwritten by most recently received packets of data over time.
In an alternative embodiment packets of data can be selectively stored in a memory to generate a series of packets of data for selected display, such as for example, a series of packets of data representing the highlights of a broadcast sporting event.
In one embodiment the speed of the display of data from the memory can be selected, and may be, for example, selected to provide a slow motion display of the data, or even a freeze frame effect.
In a yet further aspect of the invention there is provided a receiver for the reception of transmitted data and generation of a display of the video data on a display screen connected therewith, said receiver including a physical memory in which video data is stored and from which, for a time period following display, said video data can be selectively retrieved to create a video display on the display screen and characterised in that said memory includes a first portion defined as the portion of the memory defined between the producer and consumer pointers which receives the most recently transmitted data received by the receiver at each instant, and a remainder portion of the memory and in which is stored, in sequence, packets of data which have previously been received and displayed and which are transferred from said first portion as producer and consumer pointers move around the circular memory configuration.
The invention as herein described provides novel features in that it can provide a freeze frame functionality, can allow the replay of previously displayed video clips and can allow the replay of the same as many times as required. In other functions, the invention also provides for slow motion functionality and allows for the variation in slow motion speed as required.